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J4A.0 ICD-10-CM Code: Restrictive allograft syndrome

J4A.0 maps to CMS-HCC V28 276 (RAF 2.531). Documentation must support MEAT. MEAT criteria · RAF calculator · HCC Buddy coding tools

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FY 2026 Apr update / Diseases of the respiratory system (J00-J99) / Chronic lower respiratory diseases (J40-J4A)

J4A.0

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Restrictive allograft syndrome

A serious complication that can occur after a lung transplant where the donor lung gradually loses function due to rejection and scarring.

Buddy the Bee presenting code insight

Buddy Insight

Restrictive allograft syndrome is a form of chronic lung allograft dysfunction characterized by persistent decline in lung function with a restrictive pattern (decreased total lung capacity) following lung transplantation.

CMS-HCC V28

HCC 276

RAF 2.531

CMS-HCC V24

HCC 186

RAF 0.832

ACA/HHS

HCC 158

Varies by metal level

ESRD/PACE

HCC 186

RAF 0.138

RXHCC

HCC 396

Not separately weighted

Code Book Path

Official
J4AChronic lung allograft dysfunction
J4A.0Restrictive allograft syndrome

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for J4A.0 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for J4A.0 in this effective period.

Related Child Codes

Official
J4A.8Other chronic lung allograft dysfunction
J4A.9Chronic lung allograft dysfunction, unspecified

Includes

Official

ICD-10-CM does not list Includes notes for J4A.0 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for J4A.0 in this effective period.

Code First

Official
  • , if applicable:
  • heart-lung transplant rejection (T86.31)
  • lung transplant rejection (T86.810)
  • other complications of heart-lung transplant (T86.39)
  • other complications of lung transplant (T86.818)

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for J4A.0 in this effective period.

Code Also

Official
  • , if applicable, for mixed chronic lung allograft dysfunction, bronchiolitis obliterans syndrome (J44.81)

Buddy Documentation Tip

HCC Buddy guidance
Documentation of lung transplant history and date of transplantation
Diagnosis of restrictive allograft syndrome with decline in FVC and/or total lung capacity
Differentiation from bronchiolitis obliterans syndrome (obstructive vs. restrictive pattern)
Pulmonary function testing showing restrictive pattern: decreased total lung capacity, decreased FVC

MEAT Support

HCC Buddy guidance
Documentation of lung transplant history and date of transplantation
Diagnosis of restrictive allograft syndrome with decline in FVC and/or total lung capacity
Differentiation from bronchiolitis obliterans syndrome (obstructive vs. restrictive pattern)
Pulmonary function testing showing restrictive pattern: decreased total lung capacity, decreased FVC

Audit Caution

HCC Buddy guidance
Confusing restrictive allograft syndrome (restrictive pattern) with bronchiolitis obliterans syndrome (obstructive pattern)
Not coding lung transplant status (Z94.2) as an additional diagnosis
Using acute rejection codes (T86.81x) when the condition is chronic allograft dysfunction
Failing to recognize the high V24 HCC weight (0.91 for HCC 186) which makes accurate coding of this condition critical

Common Mistakes

HCC Buddy guidance
J4A.8 — Other chronic lung allograft dysfunction: use for CLAD presentations that are neither RAS nor BOS
J4A.9 — Chronic lung allograft dysfunction, unspecified: use when the specific type of CLAD is not documented
J44.81 — Bronchiolitis obliterans syndrome: obstructive pattern post-transplant, different from restrictive
T86.810 — Lung transplant rejection: use for acute rejection, different from chronic allograft dysfunction

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is J4A.0 an HCC code?

Yes. J4A.0 (Restrictive allograft syndrome) maps to Lung Transplant Status/Complications under the CMS-HCC V28 risk adjustment model (and Major Organ Transplant or Replacement Status under V24), with a community non-dual aged RAF of 2.531. It is billable for payment year 2026.

Coder answer: J4A.0 is billable and maps to V28 HCC 276, Lung Transplant Status/Complications. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
J4A.0
Description
Restrictive allograft syndrome
HCC (V28)
HCC 276 — Lung Transplant Status/Complications
RAF
2.531
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 276, Lung Transplant Status/Complications
2.531
V24HCC 186, Major Organ Transplant or Replacement Status
0.832
ESRDHCC 186, Major Organ Transplant or Replacement Status
0.138
RxHCCHCC 396, Allograft Complications
Not separately weighted

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work J4A.0 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for J4A.0

For J4A.0 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

  • MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
  • EEvaluate: test results, medication response, or physical findings reviewed by the provider
  • AAssess: explicit mention in the assessment or plan with acknowledgment of status
  • TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed J4A.0 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

J4A.0 is the ICD-10-CM diagnosis code for restrictive allograft syndrome. A serious complication that can occur after a lung transplant where the donor lung gradually loses function due to rejection and scarring. J4A.0 sits in the ICD-10-CM chapter for diseases of the respiratory system (j00-j99), within the section covering chronic lower respiratory diseases (j40-j4a).

Under the CMS-HCC V28 risk adjustment model, J4A.0 maps to Lung Transplant Status/Complications (HCC 276) with a community, non-dual, aged base RAF weight of 2.531. Under the older CMS-HCC V24 model, J4A.0 maps to Major Organ Transplant or Replacement Status (HCC 186) with a community, non-dual, aged base RAF weight of 0.832. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Requires documentation of lung transplant history and clinical evidence of restrictive allograft syndrome. Because J4A.0 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for J4A.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Requires documentation of lung transplant history and clinical evidence of restrictive allograft syndrome
  • •This is a post-transplant complication code; ensure transplant status is documented

Clinical Significance

Restrictive allograft syndrome is a form of chronic lung allograft dysfunction characterized by persistent decline in lung function with a restrictive pattern (decreased total lung capacity) following lung transplantation. It carries a worse prognosis than bronchiolitis obliterans syndrome and reflects the highest level of post-transplant pulmonary complication, mapping to high-value HCCs.

Documentation Requirements

  • ✓Documentation of lung transplant history and date of transplantation
  • ✓Diagnosis of restrictive allograft syndrome with decline in FVC and/or total lung capacity
  • ✓Differentiation from bronchiolitis obliterans syndrome (obstructive vs. restrictive pattern)
  • ✓Pulmonary function testing showing restrictive pattern: decreased total lung capacity, decreased FVC
  • ✓CT imaging findings: persistent opacities, pleural thickening, upper-lobe predominant fibrosis
  • ✓Current immunosuppression regimen and any recent changes
  • ✓Treatment plan and prognosis discussion

Code Also

  • , if applicable, for mixed chronic lung allograft dysfunction, bronchiolitis obliterans syndrome (J44.81)

Commonly Confused Codes

  • •J4A.8: Other chronic lung allograft dysfunction: use for CLAD presentations that are neither RAS nor BOS
  • •J4A.9: Chronic lung allograft dysfunction, unspecified: use when the specific type of CLAD is not documented
  • •J44.81: Bronchiolitis obliterans syndrome: obstructive pattern post-transplant, different from restrictive
  • •T86.810: Lung transplant rejection: use for acute rejection, different from chronic allograft dysfunction
  • •Z94.2: Lung transplant status: code additionally to identify the transplant history

Child Codes

J4A.0Restrictive allograft syndrome
HCC 276
J4A.8Other chronic lung allograft dysfunction
HCC 276
J4A.9Chronic lung allograft dysfunction, unspecified
HCC 276

Code Hierarchy

└J4AChronic lung allograft dysfunction└J4A.0Restrictive allograft syndrome
└J4A.0Restrictive allograft syndrome

J4A.0 code history

Code setChange
FY2024 (effective Oct 1, 2023)Added to the code set

Source: official CMS ICD-10-CM order and addenda files, FY2016 through FY2027.

Because J4A.0 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

J4A.0 maps to CMS-HCC V28 category 276, Lung Transplant Status/Complications. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. Because J4A.0 carries a payment HCC, you can see what it adds to a RAF score and check the documentation the chart needs before it is submitted.

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Open J4A.0 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.

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